The invention relates generally to the field of wireless identification of medical articles in a healthcare setting, and more particularly, to a system and method for the automatic and wireless tracking of inventory located in the pockets of medical article containers.
In the healthcare setting, particularly in healthcare facilities, healthcare practitioners (“HCPs”) need to have medications and other medical articles on hand to manage the treatment of patients suffering from a wide variety of ailments. To supply such articles for patient use, various medical administration methods and devices are used. A wide variety of containers has been adapted to store medical articles. One such container is an automated dispensing cabinet (“ADC”) having drawers or shelves in which medical articles, including medications, are stored for administration. Another container for providing medical articles is a tray or “code tray” which typically has multiple partitions forming “pockets” in which medical articles are placed. These trays often have a predetermined inventory with predetermined placement of each article of that inventory in respective locations in the tray. The trays are often stocked for particular purposes, such as for a surgery unit, an intensive care unit, a pediatric unit, emergency care unit, and others. In addition to the stocking of the trays and the specific location of medical articles in certain positions in those trays, ADCs and other dispensing containers also often contain medical articles that are placed in particular positions or in particular pockets of the container. This makes retrieving the needed medical article faster and more efficient since the HCP knows exactly where to look for a particular medical article in the container.
As used herein, a “medical article” is meant to refer to a wide variety of medical products, including but not limited to medications, syringes, bandages, tape, clamps, thermometers, and many other articles. As also used herein, a “container” is meant to refer to a device in which is stored medical articles. A “container” includes, but is not limited to, an ADC, the drawer of an ADC, a refrigerator, a tray, a kit, a cart, and a box.
Typically, a pharmacy is responsible for stocking dispensing containers with the required number and type of medical articles and for placing those stocked medical articles in the dispensing container in specified locations, as applicable. For example, a pharmacy stocks an ADC located at a surgical site or elsewhere in a healthcare facility, or stocks a tray and then ships the stocked tray to a particular location in a healthcare facility for use. The pharmacy is also responsible for verifying that the medications placed in a container are not expired or recalled or otherwise compromised.
Existing systems for identifying medical articles in a dispensing container include the manual-labor system in which a person visually looks in a dispensing container and reads the labels of the medical articles found. The labels have information that typically includes identification of the medical article, dose, and expiration date. The person then compares the medical articles he or she sees in the container to a list of what should be in the container and where they should be placed, if applicable. If the viewer finds any errors in the dispensing container, changes must be made to correct those errors. A more automated system is to have a bar code adhered to each medical article in the dispensing container. The person in charge of inventory tracking scans each article with a bar code reader and compares what the reader finds to a list of required articles for that dispensing device. Although the use of bar code labels increases the accuracy and efficiency of identification of a medical article, the system is manual in nature and requires that each article be manipulated so that its bar code can be scanned while not scanning the bar code of another medical article at the same time. This also requires the time to scan each article. In the case where the articles are supposed to be in predetermined locations in the container, the inventory tracker must manually refer to another document to determine if the articles in the container are in their proper locations. This bar-coding system is therefore a partial manual system.
Where an automatic system for tracking is desired, RFID is a candidate since identification data is obtained wirelessly and without having to scan article by article. RFID tags have decreased in cost, which has made them even more attractive for such an application.
In an RFID tracking system, a respective RFID tag is typically affixed to each article of inventory. In one embodiment, each RFID tag can broadcast a unique identification number which is the tag's unique serial number and that number can be associated with the identification of the medical article to which it is attached in a database. Thus the tag can be used in tracking articles. In order to read the RFID tags, an antenna is directed at the container. The antenna is interfaced with a reader that transmits interrogation energy via the antenna to the RFID tags, thereby activating the RFID tags which wirelessly respond with their unique serial numbers stored in each tag. The tags' responses are picked up by an RFID receiving antenna and forwarded to the RFID reader. The transmitting and receiving antennas may be the same antenna.
Precautions must be taken with an RFID system to avoid false readings that may be caused by backscatter signals. Simultaneous transmission and reception causes high levels of RF energy to enter the reader, ultimately limiting the reader sensitivity. Existing system designs attempt to solve this problem by either minimizing the signal reflections back into the reader or by using separate transmit and receive antennas. Lessening signal reflections via component selection has practical limitations. Using separate antennas increases the system cost and requires additional space. However, RF absorptive material placed in certain locations about the RFID-tagged medical articles in a container can attenuate RF backscatter and multi-path problems.
Current RFID systems exist that automatically verify the contents of a drawer or tray, or other container. For example, U.S. Pat. No. 8,749,356 to Hussain et al. describes a system where an RFID reader is configured and positioned within a cabinet having drawers with pockets. One or more of the drawers may have an RFID reader system. FIG. 1, which is taken from that patent, presents a perspective view of an RFID tracking system 60 which includes an automated dispensing cabinet 62. The figure shows an open refrigerated drawer 64 in the ADC containing medical articles 66 located in pockets 68 of the drawer. Although the drawing shows reference numeral 68 pointing to only two pockets, it is meant to indicate all pockets. Additional lead lines have been left off to retain clarity in the drawing. The ADC also includes a computer 70 connected to a display device 72 for visually outputting data and processed data, as well as other information as required. The computer includes a processor that is not shown. Two input devices are provided in this embodiment. The first input device is a hardware keyboard 74 and the second is a software or “virtual” keyboard that is formed by the processor and the display device 72 as a touchpad on the face of the display. Data is be output to a server 76 that may or may not be remote from the dispensing cabinet 62 and data is stored to and read from a database 78 that is stored on a non-volatile memory, such as a hard drive formed of a solid-state memory. A communication link 80 exists between the computer 70 and the server 76. The communication link may take various forms, including wireless types and hardwired types. The memory also may or may not be remote in relation to the ADC and the server.
The processor of the computer 70 may store data in the database 78 and may retrieve data from the database as needed. For example, where the medical articles 66 include RFID tags and those tags are activated, the reader in the drawer 64 will read the identification numbers of the activated RFID tags. The computer will receive those RFID tag identification numbers from the reader, communicate with the server 76 to provide the RFID tag identification numbers, and the server will access the database to find the identifications of the medical articles corresponding to the activated RFID tags. The server will then provide those identifications to the computer 70 at the ADC 62. The computer will then display those medication article identifications on the display device 72. Additionally, the server will store in the database the fact that the particular ADC has the medical article to which the activated RFID tag is attached. Communications with the server and the database may occur in real-time or by batch processing.
The drawer 64 has a front panel 82 that moves with the drawer but when the drawer is slid to the closed configuration in the ADC 62, the front panel makes electrical contact with the ADC. If the ADC has surrounded the drawer with electrically-conductive walls (“walls” are meant to include the back, top, bottom, and two side walls), the front panel 80 forms the front wall by being electrically conductive and when closed, coming into electrical contact with the other five walls. In effect, a Faraday cage is formed.
Such a Faraday cage in the ADC is more clearly shown in FIG. 2. The drawer 64 has been completely pulled out of the ADC 62 for clarity of illustration, but in the actual case, the drawer may not be removed as shown except for maintenance purposes. A portion of a Faraday cage 90 is shown and includes five walls. It will be located in the cavity 92 of the ADC. The front end 94 of the Faraday cage is open but when the drawer 64 is slid into the Faraday cage 90 when in the cavity 92, the electrically-conductive front wall 82 of the drawer will come into contact with the Faraday cage 90 thereby forming a complete Faraday cage around the drawer and the medical articles in the pockets of the drawer. The contents of the drawer will then be electrically isolated from surroundings. Electrical isolation is important for the RFID reader in the drawer. When the RFID reader is controlled to inject electrical energy into the drawer to activate RFID tags, that activation energy may travel far enough to activate RFID tags outside the drawer unless the drawer is electrically isolated. Activating RFID tags on medical articles outside the drawer will cause them to transmit their identification numbers and the RFID reader in the drawer will report that these items are in the drawer when in fact they are not. Placing the drawer in a Faraday cage or otherwise isolating the drawer's contents from the surrounding area would overcome this problem.
Also shown in FIG. 2 is an RFID reader module 96 and power 98 for that module. Data to and from the RFID reader module 96 is conducted over the communications line 100 shown. The RFID reader module 96 has necessary probes and antennas 102 and 104 located on a printed circuit board 106 to activate and read RFID tags attached to medical articles that are located in the drawer 64 pockets. The RFID reader module is located within the Faraday cage 90 in the cavity 92. In this embodiment, the RFID reader module will be located above the drawer in the Faraday cage, although other configurations are possible.
The local computer 70 of the ADC 62 in the embodiment of FIG. 2 is programmed to process the RFID data of activated RFID tags on the medical articles that are located in the drawer 64 within the Faraday cage. The local computer 70 in one embodiment is also programmed to create a database of those identified medical articles in the drawer 64 and the RFID data associated with them. The database in this embodiment is stored on a non-volatile memory device located at the local computer 70. In the embodiment of FIG. 1, the database is stored remotely from the local computer and a server is used to access that remote database. In the embodiment of FIG. 2, this remote connection is not shown but in a different embodiment it can exist. In such a different embodiment, two databases exist of the contents of the drawer 64.
Such systems have provided a major benefit to automating the tracking of medical articles. Such systems have improved accuracy, reduced the amount of time needed to conduct an inventory, and provide a cost-effective system for medical inventory control. While such systems can determine that particular medical articles are within a container, the precise location of the medical article within the container to a much higher degree of resolution would be desirable. Such system would be particularly helpful for containers having multiple pockets with predetermined prescribed contents. A system with higher resolution would be able to determine if the prescribed medical articles are in fact stored within the correct pockets.
Covered and open non-metallic trays of various shapes, dimensions, and depths are employed by many industries to store and track articles in predetermined configurations in pockets formed in the tray by non-metallic inserts. The U.S. healthcare industry, for example, stores as few as four and as many as two-hundred and fifty medications in predetermined pockets of non-metallic trays ranging from 1″ to 2″ deep (2.5 cm to 5.0 cm) and ranging in width/length size from 3″×3″ (7.6 cm×7.6 cm) to 18″×16″ (45.7 cm×40.6 cm). Verification before deployment, that a specific medication is located in its assigned pocket is critical to the accuracy and efficiency of the processes and operations in which the trays are employed, as the medications need to normally be dispensed and administered quickly. Having to spend time, as in prior systems, looking for and finding a medical article in a drawer or tray having many pockets is time consuming and inefficient.
While RFID systems currently exist to automatically verify that all articles necessary for a complete tray are located in the tray, a need has been recognized for a system that can accurately and automatically verify that each article is in its assigned pocket in the tray. Present verification of the location of each article in a tray is accomplished manually by a human operator, which is time consuming and therefore more expensive, and is prone to errors due to the tedious nature of repeatedly handing articles in small pockets and reading human-readable fine print. Scanning a bar code on a label of a medical article is helpful but still requires manual handling of the medical articles.
In the case where medical article containers exist that have predetermined contents and all contents have predetermined positions in the container, it would be desirable to scan the container with an RFID reader and tracking system to not only verify that the predetermined RFID-tagged articles exist or do not exist in the container, but also to determine more accurately where they are or where they should be in the container. In one case, it would be more efficient for an HCP to access an ADC to determine not only if a medical article is in a particular drawer but to scan that drawer for the RFID tag of that article and determine where exactly in the drawer it is.
Additionally, for those containers that have predetermined positions for medical articles in the container, it would be valuable for those pharmacy personnel who restock ADCs and trays to know exactly where a missing article should be placed. This becomes more important with larger drawers or other containers that have numerous medical articles located within them. While it is a major benefit to be able to determine that something is missing, as is available now, it is an even more important benefit to determine exactly where in the container a replacement article should be placed so that the container is returned to its required configuration. This will result in more efficient operation and more accurate inventories.
Providing an efficient and cost-effective RFID reader system where the reader can determine with precision where in a drawer or tray an RFID tagged medical article resides would enable automated tracking and replenishment of medical articles. Especially in trays or drawers where medical articles must be stored in predetermined pockets, such a system would decrease the amount of time it takes to correctly and accurately restock pockets in a container when medical articles have been removed. However, accurately exciting and reading the RFID tag or tags in just one pocket in a tray having many pockets has proven to be difficult. If the activation energy of the RFID reader strays into adjacent pockets and activates the RFID tagged medical articles in those pockets, the reader may receive the identification signals of the RFID tags from adjacent pockets and report those medical articles as being in the target pocket when in fact they are not there.
Hence, those of skill in the art have recognized a need for an inventory tracking system that automatically verifies whether an RFID-tagged article is located in a selected pocket. Moreover, there is need for an inventory tracking system that provides a cost-effective method of minimizing signal reflections when automatically verifying the specific location of articles in a container. There is a further need for an inventory tracking system that improves efficiency and reduces errors and costs associated with inventory management by automatically verifying the specific location of articles in a container. Such verification may include characteristics about the medical articles, such as expired and recalled status. The present invention fulfills these needs and others.